This invention pertains to valve assemblies, and more particularly to sanitary valves having cleanable-in-place gaskets which are field replaceable.
It has long been known to equip linearly actuated valves with relatively soft gaskets for contacting a valve seat to provide a tight seal. A common feature of prior art valve gaskets was difficulty in replacing the gaskets in the field. Installation of a new rubber or other elastic facing requires stretching and drawing over relatively large projections on the valve stem.
A further problem with the aforementioned prior art valve stems and gaskets is that they are not suitable for food handling applications. Sanitary installations require the use of non-corrosive materials, such as stainless steel and certain synthetic plastics. Further, the equipment should be easily cleanable. Ease of cleaning requires the use of components having a minimum number of crevices for food particles to lodge in during operation. In addition, built-up particles must be easily flushable during cleaning. Ideally, machinery, including valve elements, for handling consumable products should be cleanable without the necessity of any disassembly and reassembly, i.e., the machinery should be cleanable with all the components in place. Many prior art valve elements contain crevices that can trap food particles, and the crevices cannot be cleaned without laborious disassembly and reassembly or the use of longer automatic cleaning cycles.
In my U.S. Pat. No. 4,531,532 I disclosed one form of such an improved assembly. A need exists for additional or alternative forms of sanitary valve assemblies which incorporate field replaceable gaskets for sealing against the valve seat and which are quickly and efficiently cleanable in place.